1. Field of the Invention
Aspects of the present invention relate to an apparatus and method of managing power for a mobile device, and, more particularly, to an apparatus and method of managing power for a mobile device that prevents an inflow of overcurrent to the device when the device is charged.
2. Description of the Related Art
Generally, mobile devices, such as mobile phones and personal digital assistants (PDAs) have both a detachable and a rechargeable battery. These batteries are charged using an adapter when the batteries are mounted in the mobile device or when the batteries are separated from the mobile device.
Since a user of a mobile device should always carry an adapter if he/she intends to charge the mobile device while he/she is moving, a method of charging a battery of a mobile device using a universal serial bus (USB), which is a peripheral device connection standard of a computer, has recently been used. According to this method, a USB port provided on the mobile device is connected to a USB port of a personal computer (PC), such as a desktop or a notebook computer, through a specified interface cable, and the battery of the mobile device is charged with power being supplied through the USB port.
FIG. 1 is a schematic view illustrating a mobile device having a battery which is charged using a general adapter. As shown in FIG. 1, an adapter 20, connected to a specified commercial power supply, is connected to a mobile device 10 through a specified interface cable 21. In this case, the adapter 20 converts a commercial power supply (e.g., an AC power supply) into a DC power supply having a specified voltage level, and supplies the converted DC power supply to the mobile device 10. Accordingly, a battery of the mobile device 10 is charged with the DC power supply being supplied through the adapter 20.
FIG. 2 is a schematic view illustrating a mobile device of which the battery is charged using a general PC. As shown in FIG. 2, where a port provided on a mobile device 10 is connected to a port provided on a PC 30 through a specified interface cable 31, either the mobile device 10 transmits/receives data to/from the PC, or a battery of the mobile device 10 is charged through the interface cable 31. This method of charging a battery of a mobile device through a PC is frequently used by office workers since most office workers use PCs for their business.
However, where a battery of a mobile device is charged using the port provided on the PC 30, a power level that is supplied through the port is generally fixed, while an adapter to charge a battery of a mobile device is manufactured according to the standard of a power level (e.g., voltage and current) suitable for a specified mobile device. For example, the voltage/current that can be supplied through a USB port of the PC 30 is generally set to 5V/500 mA.
On the other hand, if the mobile device is in a low-battery state, i.e., if the power required to drive the mobile device 10 is insufficient, the mobile device 10 maintains a minimum power level to protect the system. Generally, when the mobile device 10 maintains the minimum power state, the mobile device 10 is maintained in a power-off state.
Generally, no abnormal phenomenon occurs when charging the battery of the mobile device 10 through the port provided on the PC 30 where the power of the mobile device 10 is turned off due to the low-battery state of the mobile device 10. However, when a user turns on the power just after the battery is charged, the mobile device 10 instantaneously secures current required to drive the system of the mobile device 10. This may result in overcurrent flowing into the mobile device 10. If the overcurrent flows into the mobile device 10, the voltage level required to drive the system of the mobile device 10 is relatively lowered to cause the necessary voltage level to not be secured.
Accordingly, as soon as the user turns on the power of the mobile device 10, the mobile device 10 may be switched to the minimum power state, or an abnormality may occur in the system of the mobile device 10.
Korean Patent Unexamined Publication No. 2004-9662 discloses an apparatus and a method of automatically turning on the power of a mobile communication terminal when the charging of a battery of the mobile terminal is completed where the power of the mobile terminal is turned off. However, this publication does not disclose a scheme of preventing an inflow of overcurrent to the mobile terminal when the power of the mobile terminal is turned on simultaneously with the start of charging the battery in a state that the mobile terminal is in a low-battery state.